Along with increasing advancement of a current Fiber to the Home (FTTH) technology, home and abroad telecommunication operating companies are gradually improving their capabilities in providing bandwidths for user homes, and have had capabilities of providing 1,000 M for each building and providing 100 M for each home. However, FTTH implementation cost is relatively high and an investment proportion of FTTH cost of last hundred of meters is highest, which causes lower rate of return on investment of FTTH and excessively long investment recovery cycle, and thus the operating companies adopt various segmented FTTH manners which are more economical and practical instead. In order to provide higher bandwidths and more efficient service for users, the operating companies arrange, according to practical conditions, optical nodes at positions closer to the users as much as possible, and extend fiber deployment to the last level of distributed points to implement Fiber to the Distribution point (FTTDp). A manner of twisted pair, Ethernet cable, coaxial line, power line or the like instead of fiber is adopted as an FTTH medium to implement direct FTTH. An access technology also includes a Very high bit-rate Digital Subscriber Line (VDSL), a Local Area Network (LAN), an Emergency Changeover Order (ECO) signal, a Power Line Communication (PLC) manner, Gfast and the like.
In an FTTDp scenario, a DPU is flexibly deployed, and is usually deployed at an outdoor information box, an outdoor line pole, an outdoor entrance door, an indoor house basement, an indoor connection hole and the like. Due to complexity of an access environment, it is difficult to supply power to the equipment. When laying a dedicated electric wire from a public power supply to the DPU, it may increase system deployment cost. Since the DPU is usually at a distance of smaller than 200 meters away from a user terminal, power may be reversely supplied to the DPU through user-end equipment.
However, when multiple user terminals connected to a DPU reversely supply power to the DPU, how to ensure fairness among users and transparency on supplying power is a prime problem. Mounting and deployment conditions of the DPU are relatively complex and flexible, it is necessary to utilize an existing access medium such as a twisted pair, an Ethernet cable and a coaxial cable when a user side reversely supplies power to the DPU, wherein reverse power supply with the twisted pair is one of typical scenes. In addition, there are a lot of Plain Old Telephone Services (POTSs) of a user in an existing network, wherein the POTSs are based on Public Switch Telephone Network (PSTN). It is required a long time to completely replace telephone equipment corresponding to these POTSs with Voice over Internet Protocol (VoIP) equipment, However, when analogue voice service communication between the DPU and the POTS telephone equipment is required, due to that the POTS telephone equipment is narrowband voice and analogue telephone equipment, transmission on the same twisted pair may cause the problem of coexistence of direct current voltages and low-frequency signals (such as a working voltage of the telephone equipment, 25 Hz telephone ringing and host dialing) with reverse power supply on the equipment. Therefore, user-end equipment is required to be compatible with existing POTS voice equipment to ensure that the POTS telephone equipment may still work normally in a reverse power supply process of the user-end equipment when reversely supplying power to a DPU through the twisted pair.
Therefore, there exists the problem that reverse power supply and normal operation of a POTS telephone may not coexist in a related art.